Liquid fuel pumps for internal combustion engines



y 1963 F. M. EVANS ETAL 3,091,230

LIQUID FUEL PUMPS FOR INTERNAL COMBUSTION ENGINES Filed May 4, 1961States This invention relates to liquid fuel pumps for internalcombustion engines, and of the kind comprising a rotary head in which isformed a transverse bore, at least one plunger in the bore, and annularcam surrounding the head, said cam being adapted to impart inwardmovements to the plunger or plungers as the head rotates, and adistributor rotatable with the head and having formed therein passagesthrough which fuel is conveyed to and from the bore in the head.

In such pumps the plunger or plungers are moved outwardly by the fuelfed to the bore in the head, and the displacement of fuel by the inwardmovements of the plunger or plungers causes fuel to be injected to theengine cylinders in turn through the distributor as the latter rotates.Moreover, it is usual to provide stops on the rotary head for limitingthe outward movements of the plunger or plungers, thereby limiting thestrokes of the plunger or plungers and determining the maximum quantityof fuel which can be fed to the engine. Such stops have usually beenadjustable, but it has been necessary to dismantle the pump at least inpart to effect such adjustment.

The object of the present invention is to provide in a pump of the kindspecified convenient means whereby the predetermined maximum quantity offuel which can be fed to the engine can be adjusted without dismantlingthe pump.

According to the invention a pump of the kind specified includes atleast one subsidiary cam ring surrounding the head, said cam ring beingadapted to co-operate with the plunger or plungers in limiting theoutward movement thereof while fuel is being fed to the bore in therotary head, and means for imparting angular movement to said cam ringfrom the exterior of the pump.

In the accompanying drawings, FIGURE 1 is a part sectional side view,and FIGURE 2 is a sectional end view of an example of the invention,FIGURE 1 being taken on the line 11 of FIGURE 2, and FIGURE 2 beingtaken on the line 22 of FIGURE 1.

The illustrated example of the invention is shown as applied to a knownform of pump comprising a body part 3 which at one end contains a feedpump 4. The pump 4 has inlet and outlet passages in the body part, andthese passages may be interconnected through a spring-loaded reliefvalve which limits the maximum pressure which can be generated by thefeed pump.

At the other end of the body part 3 is a fuel injection pump comprisinga rotary cylindrical head 5 in which is formed a diametrical bore 6containing a pair of reciprocatory plungers 7 which co-operate, throughrollers 8 at their outer ends, with a surrounding annular cam 9.

The rotary parts of the feed and injection pumps which are adapted to berotated by the engine, are interconnected by a spindle 5a which servesas a cylindrical distributor, and in the example shown the head 5 isformed integrally with one end of the distributor. In the distributor isformed an axial passage .10 which at one end is in communication withthe bore 6 in the head, and at another position is in communication witha radial passage 11 in the distributor, the passage 11 being adapted tocommunicate in turn, as the distributor rotates, with atent ice each ofa plurality of angularly spaced passages 12 in the body part adapted forconnection to the different cylinders of the engine.

The feed pump 4 is adapted to deliver fuel to a passage 13 in the bodypart, and which communicates in turn with each of a plurality ofangularly spaced radial passages 14 in the distributor, these latterpassages opening into the axial passage 10. In action, as thedistributor and the rotary pump parts rotate, fuel fed to the axialpassage 10 by the feed pump is discharged to the engine cylinders inturn by the inward movements of the plungers 7 of the injection pumpunder the action of the cam 9, the plungers being moved outwardly by thefuel fed to the distributor by the feed pump.

In applying the invention to such a pump, there are provided at oppositesides respectively of the annular cam 9 a pair of annular cam rings '15which are coaxial with the annular earn, and, which serve to limit theoutward movement of the plungers 7 by abutting against the end portionsof the associated rollers 8 While fuel is being fed to the bore 6 in therotary head 5. The pair of cam rings 15, which are similar, each has aninner peripheral cam surface which is divided into a plurality ofequi-angular arcuate sections equal in number to the number of cylindersof the engine with which the pump is to be associated. Each section issimilarly shaped and gradually increases in radius from one end to theother.

In the outer periphery of each ring 15 is formed a notch 16 with whichis engaged a tooth 17 on a nut 18 transversible along a screw 19extending tangentially relative to the rings and rotatable from theexterior of the body part of the pump. The inner peripheral cam surfacesof the two rings are provided at corresponding positions with the abovementioned sections, and it will therefore be appreciated that theangular setting of the rings '15 will determine the permitted outwardmovement of the plungers 7 of the injection pump, while any one of thepassages 14 in the distributor 5a is in communication with the passage13 in the body part, and thereby determine the maximum quantity of fuelwhich can be fed to the engine. Moreover, it will be understood that byrotating the screw 19 to traverse the nut 13 the angular setting of therings 15 can be adjusted.

It will be understood that the invention is not limited to aconstruction employing a screw and nut mechanism as above described forimparting the angular movement to the rings 15, and that any othermechanism either manually or hydraulically or otherwise controlled fromthe exterior of the body part may be employed for this purpose.

By the present invention therefore, the maximum quantity of fuel whichcan be fed to the engine can be readily adjusted without dismantling anyportion of the pump, and may in fact be effected whilst the engine is inoperation.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

1. A liquid fuel pump of the kind specified for supplying fuel to aninternal combustion engine, and comprising in combination a rotarycylindrical distributor provided with an axial passage and with fuelinlet and outlet passages extending outwardly from the axial passage, ahead which is provided on one end of said distributor so as to berotatable therewith, and which has a transverse bore in constantcommunication with the axial passage in said distributor, at least oneplunger mounted in the transverse bore in said head, an annular camwhich surrounds said head, and through the medium of which said plungeris movable inwardly during rotation of said distributor, at least onesubsidiary cam ring which also surrounds said head, and has an innerperipheral cam surface through the medium'of which the outward movementof said plunger is limited, and movable means engaging said cam ring,and operable from the exterior of the pump for imparting angularadjusting movement to said cam ring about the axis of said distributorso as to vary the distance through which said plunger is movableoutwardly.

' 2. A liquid fuel pump according to claim 1, and having an additionalsubsidiary cam ring which also surrounds said head, and which serves inconjunction with the first mentioned cam ring to limit the :outwardmovement of said plunger, the two cam rings being disposed ooaxiallywith, and at opposite sides respectively of, said annular cam, and-beingin engagement with said movable means which serves to impartcorresponding angular adjusting movements to both cam rings about theaxis 'of said distributor, and the inner peripheries of said cam ringsbeing provided at corresponding positions with a f4 each of whighgradually increases in radius from one end to the other. i A

3. A liquid fuel pump according to claim 1, in which the means forimparting angular adjusting movement to said cam ring is movabletangentially relative to said cam ring, and is provided a tooth engagingan external notch in said cam ringf" 4. A liquid fuelpump according, toclaim 3, wherein said means has the. form of a' n'u't in engagement withand traversable'along, a rotatable screw extending tangentially relativeto said camring. Y

References Cited in thelfile of this patent UNITED STATES PATENTS2,103,314 Benedek uecrzs, 1937 2,612,110 Delegard Sept. 30, 19522,644,238 Roosa June 9, 1953 2,660,992 R oosa Dec. 1, 1953 2,898,362Brundage Aug. 11, 1959 2,929,334 Pansnai-d Mar. 22, 1960

1. A LIQUID FUEL PUMP OF THE KIND SPECIFIED FOR SUPPLYING FUEL TO ANINTERNAL COMBUSTION ENGINE, AND COMPRISING IN COMBINATION A ROTARYCYLINDRICAL DISTRIBUTOR PROVIDED WITH AN AXIAL PASSAGE AND WITH FUELINLET AND OUTLET PASSAGES EXTENDING OUTWARDLY FROM THE AXIAL PASSAGE, AHEAD WHICH IS PROVIDED ON ONE END OF SAID DISTRIBUTOR SO AS TO BEROTATABLE THEREWITH, AND WHICH HAS A TRANSVERSE BORE IN CONSTANTCOMMUNICATION WITH THE AXIAL PASSAGE IN SAID DISTRIBUTOR, AT LEAST ONEPLUNGER MOUNTED IN THE TRANSVERSE BORE IN SAID HEAD, AN ANNULAR CAMWHICH SURROUNDS SAID HEAD, AND THROUGH THE MEDIUM OF WHICH SAID PLUNGERIS MOVABLE INWARDLY DURING ROTATION OF SAID DISTRIBUTOR, AT LEAST ONESUBSIDIARY CAM RING WHICH ALSO SURROUNDS SAID HEAD, AND HAS AN INNERPERIPHERAL CAM SURFACE THROUGH THE MEDIUM OF WHICH THE OUTWARD MOVEMENTOF SAID PLUNGER IS LIMITED, AND MOVABLE MEANS EN-